This proved to be controversial and caused many delays in final alignment selection for the north leg, postponing its construction by several years.

Indiana highway officials recognized the value of having the route be a full circumferential, so using non-Interstate federal funding and employing a temporary designation of SR 100, they planned a separate 17th segment northward between I-65 at its exit 123 and the north leg of I-465 in Boone County.

[3] State highway officials concentrated on building the west and south legs of I-465 early in the overall project, since they were the missing portions of the SR 100 concept.

Construction began in 1959, and the first section of the I-465 beltway to be completed was the portion on the west leg between I-65 near Eagle Creek Park and I-74/US 136 in Speedway.

[3] With SR 100/Shadeland Avenue connected to the full southern and western bypass of Indianapolis, work on I-465's east leg slowed, delaying the opening of the next segment over three years.

In January 1968, two sections of the east leg, between US 36/SR 67 (Pendleton Pike) and the SR 100 junction near Raymond Street, were completed and opened a day apart.

On October 23, 1968, the section of I-465 between Pendleton Pike and 56th Street at Shadeland Avenue was finished and opened to traffic, completing the east leg's eastern bypass of SR 100.

The next month, in November 1969, the north extension of the west leg was completed and signed as I-465 (although it was considered to be "added mileage" by the Federal Highway Administration (FHWA) since it was built to Interstate standards using non-Interstate funds by Indiana), but only the portion between I-65 and 86th Street was opened to traffic because the segment of the north leg to which it would connect was not yet complete.

At that time, the final connection on the north extension of the west leg to 86th Street was also opened, leaving only one remaining gap in the entire I-465 route.

The first of the major post-completion rebuild and expansion projects occurred from 1999 to 2002, when the heavily traveled northern section of the east leg was modernized and expanded to as many as 13 lanes in one short portion.

[4] Between 2004 and 2005, the north extension of I-465's west leg between I-65 and I-865 was rebuilt to widen and update the freeway in this heavily traveled section located along the western edge of the massive Park 100 commercial and industrial development.

This segment was rapidly becoming functionally obsolete due to continued growth of that complex as well as that of other nearby residential and commercial projects in Pike Township.

On the mainline, dual auxiliary lanes were added in each travel direction between these interchanges and the 79th Street grade separation over I-465 was demolished and rebuilt to allow for the widened freeway below.

INDOT completed an $800-million (equivalent to $1.05 billion in 2023[6]) project called Accelerate 465 to refurbish and reconfigure the original west leg of the loop between July 2007 and December 2012.

The beltway's mainline was reconstructed with additional travel and auxiliary lanes being added in two separate segments—from east of Meridian Street to Allisonville Road and from a point at the southeast end of the I-69/Binford interchange southward to Fall Creek.

[10] As part of its Operation Indy Commute project, INDOT began work in 2013 to widen I-65 on both its northbound and southbound mainlines from exit 103 at Southport Road northward to the junction with I-465's south leg, which would also be modified.

In addition, grade separations over I-465 were replaced on Sherman Drive and Carson Avenue to allow for longer and wider approaches to this busy junction.

[11] As part of the major project to upgrade 13 miles (21 km) of US 31 in Hamilton County to a full Interstate-standard freeway, the I-465 north leg interchange at Meridian Street (exit 31) was reconfigured between October 2013 and December 2015 (with some additional work continuing until November 22, 2016) to the present partial directional (system interchange) design which allows for free-flow movements to or from the new US 31 freeway to the north.

[citation needed] In 2022, construction began on Clear Path 465, a project involving widening I-465 between the White River and Fall Creek, as well as rebuilding the interchange of I-465 and I-69 in the northeast region of Indianapolis.

As part of this project, the interchange will be reconfigured to provide a direct movement for traffic on I-69 to continue onto I-465 southbound, which will be concurrent with I-69 upon the interstate's completion.